For which handheld was Kingdom Hearts 3D: Dream Drop Distance first released?

Kingdom Hearts 3D: Dream Drop Distance was first released for the Nintendo 3DS.

Square Enix developed the game specifically for Nintendo's glasses-free 3D handheld. It is a 2012 action role-playing game centered on Sora and Riku taking the Mark of Mastery exam. Their mission sends them through sleeping versions of worlds while preparing them for the possible return of Master Xehanort.

The game was first released in Japan on March 29, 2012. European, Australasian, and North American releases followed later that year. Its 3DS design helped distinguish it from earlier handheld Kingdom Hearts titles, including the Nintendo DS games 358/2 Days and Re:coded and the PlayStation Portable's Birth by Sleep.

A common source of confusion is the later Kingdom Hearts HD 2.8 Final Chapter Prologue release. That collection brought an updated version of Dream Drop Distance to newer platforms, but those ports came years after the original handheld launch. The first-release platform remains the Nintendo 3DS.